Collaborative Research: Genesis of Primitive, High-Sr Lavas in the Western Aleutians

智力价值：这项研究是由四家机构合作进行的，支持对2005年7 - 8月在阿留申群岛西部海底进行的一次巡航中通过疏浚火山收集的火山岩进行地球化学研究。初步结果表明，岩石中含有大量的原始熔岩，其中不仅包括玄武岩，还包括安山岩和英安岩，其微量元素组成异常。该项目的目标是分析其中100个样品，并利用这些数据对岩石学和地球化学过程进行建模，从而得出它们的成因和演化，并将这些结果置于俯冲带岩浆过程的背景下。分析工作将集中在包括主要元素和微量元素在内的全岩石地球化学上，确定100个样品中一部分样品的Pb、Sr、Nd和Hf同位素比率，对一些最新鲜的含玻璃熔岩中的斑晶和玻璃包裹体进行电子探针研究，并使用离子探针确定橄榄石和辉石寄主的辉石斑晶和玻璃包裹体的微量元素组成。华盛顿卡内基研究所（Carnegie Institution of Washington）的一名合作者将对玻璃内含物中的挥发性和轻元素进行一项小型、无成本的试点研究。更广泛的影响：这项研究涉及四个机构之间的合作，并将支持南卡罗来纳州一所大学的博士生和本科生，这是EPSCoR州。该项目还聘请了一位海洋科学方面的新研究员。地球化学分析将支持共享分析设施，从而帮助维持科学基础设施。数据将在知名的地球化学数据库（包括GeoRock和PetDB）中存档并向公众提供。

Intellectual Merit: This research is a four-institution collaboration that supports geochemical studies of volcanic rocks collected by dredging volcanic the western Aleutian seafloor during a cruise carried out in July-August 2005. Preliminary results show that the rocks contain a large proportion of primitive lavas that include not only basalts, but also andesites and dacites with unusual trace element compositions. Goals of the project are to analyze 100 of these samples and use the data to model the petrological and geochemical processes leading to their genesis and evolution and placing these results in the context of subduction zone magmatic processes. Analytical efforts will focus on whole-rock geochemistry including major and trace elements, determine Pb, Sr, Nd and Hf isotopic ratios on a subset of the 100 samples, carry out electron microprobe studies of phenocrysts and glass inclusions in some of the freshest glass-containing lavas, and use the ion probe to determine trace element compositions of pyroxene phenocrysts and glass inclusions hosted by olivine and pyroxene. A small, no-cost pilot study of volatile and light elements in glass inclusions will be carried out by a collaborator at the Carnegie Institution of Washington. Broader Impacts: This research involved collaboration between four institutions and will support a PhD student and undergraduates at a university in South Carolina, which is an EPSCoR state. The project also engages a new investigator in ocean science. Geochemical analyses will support shared use analytical facilities thereby helping sustain the infrastructure for science. Data will be archived and made available to the public on well know geochemical databases, including GeoRock and PetDB.